1. Field of the Invention
This invention relates to machine embossable tape and more particularly to a novel embossable tape which exposes luminous indicia when embossed.
2. Description of the Prior Art
Heretofore, it was known that reflective or luminous adhesive tapes could be made by applying the luminous material to one surface of a flexible tape or webs and an adhesive to the reverse side of the tape. Such prior art luminous tapes exposed the luminous material to the atmosphere which caused deterioration. Transparent layers have been placed over the face of the luminous material to protect it from the environment. Such tapes have introduced problems when the transparent layers were added as a hardenable liquid because the transparent layer became brittle causing cracks and leaks. When flexible transparent layers were applied over the luminous material, there was a problem of selecting a transparent adhesive which would hold the outer flexible sheet without disturbing the luminous material. It is generally known that when luminescent materials are mixed with adhesives, paint or a carrier vehicle that some of the luminous nature of the material is lost.
Heretofore embossable tapes generally had an opaque cold embossable base sheet of paper, cardboard, metal, plastic or other deformable material and had a plasticized film formed on the front face thereof. Such tapes usually had an adhesive layer on the reverse face of the base sheet which was covered with strippable backing. Such cold embossable tapes are commercially well known and need not be described in detail. When such embossable tape is cold formed, the plasticized film ruptures at the embossed regions exposing the permanent embossment of the contrasting color backing.
Transparent sheet or film material is known which can be cold formed and remain transparent and flexible. Further, transparent plastic materials are available which become substantially opaque when embossed or strained beyond their yield point.